Abstract

We performed capacitance–voltage analysis of 5-nm-thick LaAlO3/SrTiO3heterostructure containing two-dimensional-electron-gas (2DEG) at the interface. The complex impedance of the heterostructure was measured as a function of frequency for a wide range of gate biases. The impedance spectra showed a different behavior above and below an applied voltage of −1.8 V. The capacitance determined from the impedance was approximately 1.2 nF above −1.8 V and was drastically reduced to ∼0.01 nF below this voltage, owing to depletion of 2DEG and the insulating SrTiO3 underneath it. This suggests that devices utilizing LaAlO3/SrTiO3 can facilitate switching operations in a very small voltage range.

Received 25 February 2013Accepted 12 March 2013Published online 20 March 2013

Acknowledgments:

The authors gratefully acknowledge support by the Korea Institute of Science and Technology (KIST) through 2E24001 and Converging Research Center Program through the Ministry of Education, Science and Technology (2012K001306).